Process for the production of a weatherproof oxide layer on electron metal



Patented Sept. 13, 19 27.

. NITED STATES. RATENTgbFFlCi j WELLY rmrna, or nunnn'naao, GERMANY,assrenon- 'ro J. a soanmma nacnrl V nnrssznueranarx a.-e., or nunnmmae,GERMANY.

- raocnss roa run rnonuc'r on or a No Drawing. Application filed Kay 22,1924", Serial No. 715,251, and in Germany July 4, 1828.

The surface of the commonly used electron metal i. e. of a manganesebase z1ncaluminum alloy which as regards quality,

weight ium, is not weather-proof but changes under the action oftheatmospheric air after a short time. Numerous processes have beeninvented with the view to do away with this disagreeable property ofthis metal by producing a weather-proof protecting coatlng on the metalby oxidation. The known processes give however no satisfactory result asthey all use acid solutions.

' only on the surface of the oxide coating but permeating through theentire layerof oxide.

The process according to this mvent-ion.

ma for instance be carried through in the -fol owin manner The e ectronmetal or the articles made from it are dipped into an alkaline solutionj heated to a proximately 110 to 120 (3., for instance so umhydroxide,in combination with substances which give off oxy n, for

instance potassium nitrate, ferric by rate or the like. When thearticles to be oxidized are being dipped into. the alkaline solutionthey are preferably slightly moved to and fro.

After a short time a very uniform oxide coating is produced whichstrongly adheres to'the fundamental metal and is of grey color,that isof similar appearance as the electron metal. After animmersion of 'about20 minutes the oxide coating is for instance 0,05 mm. thick; it mayhowever be produced at'- a thickness 'of 0,30 mm. and more. The electronmetal is dried after it has been taken out of the solution whereupon theoxide coating may be burnished.

The oxide coating may be oolored'lo al- I kaline proof coloringsubstances of any ind, preferably by means of aniline dyes. The

yes are preferably added to the alkaline and appearance is similar toalumin-' st time, the coloring of layer ma hydrocar solution so that theoxide coating produced, is colored. The oxide coating ma howeverwna'rnnnraoor oxmn LAYER on mamm- IETAL. I

be colored later on after the drymg of the electron metal by separatetreatment with alkaline proof solution of dyes and metal oxides. I p Thecoloring substance permeates the en? tire oxide coating so that -thecoloring quite as durable as the oxide coating.

By the above described treatment of the electron metal with a hotalkaline solution in combination with substances, giving, off oxygen thestructure of those parts o the metal is changed whichis permeated by thesolution and the coloring substance camper meate this changed layer ofthe metal.

' To produce multi-coloredoxide coatings, colorin substances soluble in'oil, which prefer-a l are also alkaline proof, and to which oi wax,Vaseline, paraflin, or anyother fat of viscid' consistency is added, arepainted in the desired design on the metal articlehaving the oxidecoating, whereupon the metal article with the palnt is heated for about10 seconds at a temperature of about 150 C. and cooled slowly.. Thecoloring. substance 'will then have permeated the entire oxide layer sothat it is as lasting The metal thus treated may as this layer.

be burnished.

The color is preferabl aid of a stencil so that il;

put on with the signs of any kind and colors can be produced with sharp.out-

lines or not. Very efiective malticolor effects can thus be produced.

The finished colored or uncolored oxide be subsequently impregnated withone oils or the like to make the same to a higher degreeresistant'against the influences of the weather or even waterproof. Asthe structure of the metal. has been altered at the production of theoxide layer the hydrocarbons, oils or the like can penetrate into themetal, like the coloring substances. I

The above described processv may further be used for other metalspossessing similar properties as the electron metal. This process ishowever especially important for the manufacturing of slide rules ofmetal, as they can be colored in the same manner as the wood sliderules. The parts of a metal slide rule corresponding to the parts atwhich the wood" is visible in wooden slide rules are colored brownandthe parts of the l metal slide which correspond to the parts of inusing for the oxidation a solution 0 ydroxide and of chemical substancessodium I giving off oxygen, such solution containing potassium nitrate,said solution being free from any oily matter. g

2. A process of producing a weather-proof protecting coating onelectron-metal and similar metals by oxidation, consisting in us ing forthe oxidation a solution of sodium hydroxide and of chemical substancesgiving ofi oxygen, such solution including ferric hydrate, said solutionbeing free from any 011 matter.

n testimony whereof I aflix my signature.

WILLY PIEPER.

